Minimally invasive surgery (MIS) is commonly known in the art as surgical procedures that are performed through incisions that are considerably smaller than incisions used in traditional surgical approaches. The less invasive nature of MIS procedures presents several advantages which promote the continued use thereof. Among other things, the smaller incisions of MIS procedures may help minimize trauma to soft tissue, reduce post-operative pain, promote earlier mobilization, and shorten hospital stays as well as rehabilitation times.
However, the reduced incision size of MIS procedures tends to limit the surgeon's ability to access or view anatomic surfaces within the region of interest. To overcome such limitations, the surgeon may use a bent tip probe, such as the probe P shown in FIG. 1, which can be inserted into the incision and used to gain better access to anatomic surfaces within the exposure surrounding the particular region of interest. In particular, the tip at the proximal end of the probe may be fitted with an optoelectronic transducer or any other means capable of detecting positional changes in the anatomic surface relative to the probe tip and generating electronic pulses or signals corresponding thereto. As shown in FIG. 1, for example, a bent tip probe P may be used to reach anatomic surfaces S having a normal axis N that is perpendicular to the direction of surgical access Daccess. As further shown in FIG. 2, for example, in a configuration adapted for use with an optical position transducer, a bent tip probe P may be used to gain access to anatomic surfaces S having a normal axis N that is parallel but in opposition to the direction of the line-of-sight Dsight.
Bent tip probes may generally be used to register the pose, such as the position and orientation, of a computational representation or digitized model of an anatomic region obtained from medical imaging devices to the actual pose of the corresponding anatomic region within a surgical workspace. In particular, the distal end of the probe may be coupled to a position sensing device which may employ, for instance, an array of optically detectable markers, a mechanical tracking arm, an electromagnetic tracking system, or any other suitable means configured to track the position of the probe tip relative to the position sensing device. By tracking the probe tip and using other known relationships between the position sensing device and the surgical setting, quantitative points for the registration between the digitized anatomy and the actual anatomy may be obtained. Based on the quantitative points, the surgeon may be able to register and synchronize the pose of the digitized anatomy with its actual counterpart prior to or during surgical procedures.
In alternate applications, the bent tip probe may be used to provide a more detailed image representation or model of a particular anatomic region that may otherwise be difficult to view without making additional incisions. In such applications, the distal end of the probe may be attached to a surgical tool, such as a tool that may be used in conjunction with tracking devices, haptic or force-feedback devices, imaging devices, and/or any other computer-assisted device designed to assist a surgeon with surgical planning and/or surgical navigation. A computer system associated with the surgical tool may receive the signals generated by the transducer in response to detected changes proximate the probe tip, and use the corresponding positioning data to generate digitized models of the surfaces within the anatomic region for the surgeon to use as reference.
Although bent tip probes may provide some useful insight on anatomic surfaces that are situated in areas of limited access, there is still room for improvement. For instance, as bent tip probes are attached to a position sensing device or a surgical tool, the positional flexibility or the range of movement of the probe is limited to that of the device or tool to which it is rigidly coupled. In order for a surgeon to access all of the relevant anatomic surfaces of a particular region of interest, the surgeon often needs to readjust the angle and/or direction of the probe tip, thus requiring readjustment of the rotational position of the probe relative to the surgical tool. However, as the consistency of the positioning data captured at the probe tip is dependent on the position of the probe tip relative to the surgical tool, a calibration for an arbitrarily bent tip probe is required after each adjustment. Repeated probe calibrations, especially for each of several anatomic surfaces within one region of interest, can be quite cumbersome, time consuming and cause undesirable interruptions.
Furthermore, proper use of bent tip probes currently available in the art requires consideration for two generally independent orientation constraints, for instance, constraints associated with the probe tip and constraints associated with the sensor end of the probe. Optimal orientation of the probe tip may require the tip to be normal to the digitized surface. Optimal orientation of the sensor end may be specific to the type of sensing scheme being employed. A sensing scheme using an array of markers, for example, may require the line-of-sight to be oriented toward the optical sensor. A mechanical tracking arm employing an instrumented spatial link may be constrained by simple kinematics of the probe itself. Rotation of the handle may also be another consideration for setting the orientation of the probe. The multitude of such constraints and the interdependencies therebetween increases the complexity of each calibration and adjustment, thus increasing the risk to inaccuracies and consuming more time.
Accordingly, there is a need for a simplified surgical device that can be used to facilitate MIS procedures without requiring multiple calibrations per use. Moreover, there is a need for a surgical probe that can gain access to more anatomic surfaces of a particular region of interest from a single pre-calibration without compromising the accuracy of the positioning data collected and eliminating interruptions or delays. There is also a need for a probe that enables user-selectable orientations with substantially less variables and constraints while preserving overall utility and functionality. Specifically, there is a need to provide a probe with a tip position that is independent of the orientation of the probe.